Electric tool-driver.



No. 852,(926. PATENTBD MAY '7, 1907. y A. F. CARVER 6L J. N. STOUT.

ELECTRIC TJOL DRIVER,

LPPLIOTION FILED DBO. 21,1905.

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UNTE STATES' ALLEN F. CARVER ANB drhldlz N. Wi TO AlllltlCAN INVENTIGNS (i-,1 RTON @i .elli-1W JERSEY.

ELEGTRMI? TGLMDFEEVER,

No. senese.

Specification of Letters Patent.

Patented re-y r, reo?.

Application filed December 2l., 1905. Serial No. 292,829.

5 hatten, in 'the city and State ol New 1rorli,

he Vo invented n new and useful Electric Tool-Driver, of which the following is a speciiication. v

Our invention relates to electric tool drivers 1o and more particular-lyT to en electric tool driver in which e reciprocating hammer is caused to deliver blows .in rapid succession on a tool holder by the energizing and de-energizinr ol' eleotromagnet coils.

The objects are to provide en auxiliary switch in connection with vthe handle ol' the tool for operating en eloctroinagnel to make and breakv the current to throw the driver linto and out ol operznion to provide means .zo lor utilizing the return stroke olE tho'hammer to cool the electroinagnet coils; io provide :t tool holding chuck which shall coopera-te with the hammer to increase the Ymagnetic lorce and decrease the cost ol' the tool proper; lo provide simple and ellieient means l'or holding the switch block and its lniusing pla-te in position. and to provide means lor ma.teriall)v reducing the eddies oi' magnetic current in` both the hinniner end shell.

l/Vith these objects in View, our invention consists in certain lentures ol ednstruction and combinations of ports ns will be hereinafter described and pointed out in the claims, In the ecconipanyingbr drawings, Figure 1 View of the tool driver in longitudinal seotion, Fig'. 2 is a transverse section in the pleno ol the line A---A oli Fig'. l Fig. 3 is a partiel side elevation of the lnnidle partly broken away, Fig. 4 is top plan ol" the seine with housing plete removed, Fig. 5 is an end View oi 'the han-nner proper, Fig. 6 is an enlarged transverse section et the shell, and Fig. 7 is a diagralnrneticel View showing the electrical eonnections between 'the several coils, switches, coininutstors and source of electrical energy. The driver consists of zin.y outer shell 1, un inner tube 2, spaced from the. ouier shell, a, Series of coils, in the present instance three, denoted by 3 4, and 5, located between the shell '1 and inner tube 2, ay fool; piece ll interlocled with the foot end of the shell and pro- "aided with e stem 7 extending within the foot end of the inner tube end e heed engage rent with the head ends ol and inner tube by en annular ndt Q.

The handle is hollow and has lined therein n bloeli 10 of insulatingr nniterial (ni-living two Contact plates 11 and .l2 spaced apart and arranged to be bridged by a. piece ol conductingl material 13 on the inner end oi a plunger le seated in the handle and provided with a retroeting spring 15, which tends lo hold the bridge piece 13 out of Contact with the plates 1 1 and 12 when pressure is removed from the plunger.

4The block 10 held in position by the single bolt 15 which passes through the handle and serves to hold, et the eine time, the housing plete 17 in its position. The housing plete '17 is further neld against displacement by pins or stues 1S projectingl oulwftrdly from the side oi. the body of the hendle and arranged to enter holes or sockets 19 in the plate.

The handle e is provided with :i hollow stem 2() which projects into the head ond ol the shell, receiving; therein the head end ol the inner tubes 2 and furnishing' a seat for the reciprocating,` piston 21, the latter having located within its hollow outer ond a cushioning` spring; for moving the piston sway from the head ol' the stein 20.

lhe space between the piston 21 and the heed ol: the stem 20 is in ell'ect :i dash pot the eoinpressetleir from which is directed to the exterior oi the elerlromagnet coils tlnough discharge duets, in the present instance three denoted by 23, 24.', 25. rlhe number ol2 ducts may be increased or diminished at pleasure. Air is admitted to the dash pot tlnough e duct 26 extending through the bese of the handle.

'lhe several duets 23 to 25 inclusive, are provided with spring actuated discharge valves 235, the springl pressure on which is su'llieient to permit the valves to open when the air pressure within the dash pet reaches .e predetermined point. The duct 25 is also provided with an inlet Valve 26".

The loot piece 6 is provided with e central bore 27 for receiving the shank 28 of the tool holder 2Q. The outer endtof the tool holder is provided with s socket 3Q for the reception of the shank ofthe tool The tool may IOO 'pin 32.

The inner end ci the shank 28 of the tool holder is provided with an enlarged head 33,

of some material highly receptive of mag netic influence.

This head 33 may be secured in any suitable manner, lor instance, by means of a bross pin 34. The head 33 is located within the held of the driving magnet coil 4 and serves tomaterially increase the force of the hammer blow by attractin the hammer and in turn to promptly repo the hammer when the demagnetizing coil is energized. This head also serves to increase area of the surface which receives the impact of the hammer and thus decreases the tendency to upset the metal.

The hammer proper is denoted by 35, It is preferably an elongated cylinder, of iron or steel and is provided with radial cuts 36 extending longitudinally from,l one end to near the opposite end, the said lcuts being iilled with suitable insulating material and serving to break up what are knolvn in the art as current eddies. The shell 1 is in like manner cut longitudinally as at 37 to interrupt the current eddies which may form in it.

The contact pieces 11 and 12 carried by the block l() are electrically connected .with

the opposite poles of an electromagnet 33, in

the present instance, a solenoid, by wires 39 and 40, one of said wire sincluding a source of electric energy shown conventionally at 41. The solenoid closes and opens a switch' 42, for energizing the several coils to set the driver in operation.

A commutator shown conventionally at 43 is represented as having two segmental eon,

tact plates 44', 45, along the faces oi which the contact arm 46 travels to regulate the current through the coils.

It is to be understood that the arm 46 may be rotated by any well known or approved means, for instance by an electric motor, not shown.

The arm 46 is electrically connected with one pole of the generator 41 by a vnre 47 including the switch 42 and the opposite pole of the generator is connected with the plates 44, 45, through the coils 3, 4 and 5, asA follows A wire 48 leads from the generator to the coil 5, the wire 48 forming an electric continuation ol the wire 39 leading to one ol" the contacts of the auxiliary svtch herein above referred to. From the opposite pole of the coil 5, a Wire 49 leads to the demagnetizing coil 3, and from its opposite pole a wire 50 leads to the plate 44 el the commutator. The wire 43 by means of a branch wire also connects with one pole ol' the drivingl coil 4, its opposite pole being connected by a wire 52 with the commu tator plate 45.

The coil 3 is, for convenience, termed the dennagnetizing coil, since, either by its re verse winding or by directing the current "through it, in a direction opposite that irl which the current is passed 'through the other coils, it serves, when energized to set up in the'tool holder a repellent force for releasing the hammer as soon as its blow has been delivered.

The coil 4 is termed the driving coil as it is relied upon to draw the hammer toward the tool holder to deliver the blow.

The coil 5 is termed Vlor convenience the rc- 4tracting coil as it is relied upon in conjunction with the coil 3 to withdrawth'c hammer.

T he arrangement is such that the hammer never moves out ol a position to be inlluenced by the coils 4 and 5, and the enlarged head ol the tool holder is in position to be inlluenced by the coil 4 so that when the coil 4 is ener gized it sets up corresponding polarity in both the hammer and the tool holder which brings unlike poles toward each other in the hammer-and tool holder thereby increasing the eil'ective blow of the hammer.

The return movement ot the harhmcr also operates the visten 21 compressing its spring 22 and also tlie volume ol air behind it forcing the air out through the ducts 23, 24, 25, around the coils, within the shell, from whence it escapes through suitable outlet openings 53 in the shell.

ln operation, the operator by pushing the plunger 14 inwardly and closing the space between the plates 11 and 12 energizes the solenoid 33 and closes the main switch 42. This, assuming the parts to be in the position shown in Figs. 1 and 7, energizes the coils 3 and 5 and the hammer will be retracted, striking the cushioning piston 21 and ejecting the cooling medium. As the arm 46 travels olli the plate 44 the coils 3 and 5 will be deenergized and as the arm 46 engages the plate 45 the coil 4 will be energized and the hammer caused Vto deliver its blow assisted by the attraction of the head 33. ,lis the arm 46 leaves the plate 45, the coil 4 ,will be deenergized and as the said arm engages the pate 44 the coils 3 and 5 will be again energized and the hammer retracted.

YWhile wehavc chosen to illustrate three coils in connection with the driver, it is to be understood that the number of coils may be changed to suit the requirements of any parlticular driver.

TWhat we claim is:-

1. In an electric tool driver, the combi nation with a series of magnetic coils, a reciprocating hammer within the coils and means lor supplying an electric current to energize the coils, oic a solenoid switch ior making and breaking the main current to energize the coils, contacts in the handle of the electric tool driver electrically connected. with the poles rci" the solenoid and means `for closing the contacts in the said hand e to enlOO ergize the solenoid and 'hence operate the switch in the main circuit.

2. In an electric tool driver, including electroniagnet coils for advancing and re trac ting` `receive the impactV of the hammer on its return stroke, and ducts foi""z'i" :linitting air to .the dash plot and for discharging it around. the coils. f r

4. ln an electric tool driver, including electromagnet coils for advancing and retracting the hammer, a dash pot ,comprising a spring actuated, reciprocating pistonin position to' receive the impact of the hammer on itareturn stroke and valved ducts for admitting air to the dash pot and for discharging,r `it around the coils. l 5. In an electric tool driver including electromagnet coils for advancin and retracting the hammer, a movabletoo holder having its inner end Within the licld of the hammer driving` coil.

6. In an electric tool driver, iiif,:lu iing cicctroniagnct coils; for ad rancing and intr-acting' the hain'iner, a lool hold or having an milargcd head on ite inncr 0nd within the 'fichi of the hammer driving coil.

7. ln an elcctric tool driver including electromagnct coils for adv-ancinc` and rc'tiactingl the haninier, a toolv holder having an -niargcd head on ite inner end Within the field ol and. a tool receiving socket in ita outer ond.

8. vln an electric tool driven a block of in sulating material carrying contact platee and. seated in the handle, a housing plaie removably iitted to the side oi thc l'iandlc and a eboltextending through the block and plate and serving to hold both in position.

In testimony, that Wc claim the foregoing' as our invention, We have signed cui namen in presence of two Witnesses, this 18th day oil December 1905. ALLEN F. CARVER.

' JAMES N. STG'UT. vliitnesses:

FREDK. HAYNES, HENRY Tnnmn.

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